<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>属性选择器</title>
  <style>
    /* input[name] {
      background-color: brown;
    } */
    input[name='username'] {
      background-color: brown;
    }

    input[name^='a'] {
      background-color: rgb(130, 197, 104);
    }
  </style>
</head>

<body>
  <form action="#">
    <input type="text" name="username">
    <br />
    <input type="text" name="age">
    <br />
    <input type="radio" name="gender">男
    <input type="radio" name="gender">女
  </form>
</body>

</html>